Our Methodology

We do not sell solar. We compare it.

YourWatts is an independent comparison platform. We do not install solar, sell panels, or receive commissions from manufacturers for rankings. Some product and installer links are affiliate links — we receive a referral fee if you proceed, but this does not affect where a product appears in our rankings.

Data Sources

• Panel, battery, and inverter specifications — sourced from current manufacturer datasheets. We note the last-verified date on every product page.
• Prices — indicative market estimates based on publicly available installer quotes and wholesale pricing where disclosed. Actual prices vary significantly by location and installer.
• Tier ratings — Bloomberg NEF bankability tier for solar panel manufacturers. Tier 1 = financially bankable, not a direct quality guarantee.
• Incentive data — sourced from state energy offices, DSIRE (Database of State Incentives for Renewables and Efficiency), and direct government sources. Reviewed quarterly.

Scoring Criteria

Our "Best for X" badges are assigned based on objective data:

• Highest Efficiency: Highest published efficiency percentage under STC conditions
• Best Value: Lowest price per watt among Tier 1 panels with ≥20% efficiency
• Best Warranty: Longest linear power warranty with ≥90% at year 25
• Best Off-Grid: Largest usable capacity with LFP chemistry and ≥95% round-trip efficiency

Calculator Methodology

• Annual production = system kW × peak sun hours (NREL data by state) × 365 × 0.80 performance ratio
• Performance ratio of 0.80 accounts for inverter losses, wiring losses, temperature derating, and soiling
• Degradation: 0.5%/year (industry standard; some premium panels perform better)
• CO₂ offset: US average grid emission factor of 0.386 kg CO₂/kWh (EPA eGRID 2023)
• Tree equivalence: 21 kg CO₂ absorption per tree per year (USDA estimate)

Update Cadence

• Product specifications: reviewed when manufacturers release updated datasheets
• Pricing: reviewed monthly
• Incentive data: reviewed quarterly

Limitations & Disclaimers

All content on YourWatts is informational and should not be used as the sole basis for purchasing decisions. Solar system performance depends on local weather, roof conditions, installation quality, and equipment selection. Obtain quotes from qualified installers before purchasing.